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LK201
The LK201 is a detachable computer keyboard introduced by Digital Equipment Corporation of Maynard, Massachusetts in 1982. It was first used by Digital's VT220 ANSI/ASCII terminal and was subsequently used by the Rainbow-100, DECmate-II, and Pro-350 microcomputers and many of Digital's computer workstations such as the VAXstation and DECstation families. The keyboard layout was new at the time, adding a set of cursor and miscellaneous keys between the main keyboard and the numeric keypad. The cursor keys were arranged in what has now become the standard "Inverted T" arrangement seen on essentially all contemporary full-sized computer keyboards. The keyboard also added a Compose key to allow typing of all of the characters in the terminal's extended character set using two-stroke mnemonics, for instance produced . An LED on the keyboard indicated an ongoing compose sequence. Ergonomic considerations caused the keyboard to be designed with a very low profile; it was very t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compose Key
A compose key (sometimes called multi key) is a key on a computer keyboard that indicates that the following (usually 2 or more) keystrokes trigger the insertion of an alternate character, typically a precomposed character or a symbol. For instance, typing followed by and then will insert ñ. Compose keys are most popular on Linux and other systems using the X Window System, but software exists to implement them on Microsoft Windows, Windows and macOS. History The Compose Character key was introduced by engineers at Digital Equipment Corporation (DEC) on the LK201 keyboard, available since 1983 with the VT220 terminal. The keyboard included an LED indicating that a Compose sequence is on-going. While the LK201 introduced the group of command keys between the alphanumerical block and the numerical keypad, and the "inverted T" arrangement of arrow keys, which have become standard, the compose key by contrast did not become a standard. In 1987, Sun Microsystems released the Sun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VT220
The VT200 series is a family of computer terminals introduced by Digital Equipment Corporation (DEC) in November 1983. The VT220 was the basic version, a text-only version with multi-lingual capabilities. The VT240 added monochrome ReGIS vector graphics support to the base model, while the VT241 did the same in color. The 200 series replaced the successful VT100 series, providing more functionality in a much smaller unit with a much smaller and lighter keyboard. Like the VT100, the VT200 series implemented a large subset of ANSI X3.64. Among its major upgrades was a number of international character sets, as well as the ability to define new character sets. The VT200 series was extremely successful in the market. Released at $1,295, but later priced at $795, the VT220 offered features, packaging and price that no other serial terminal could compete with at the time. In 1986, DEC shipped 165,000 units, giving them a 42% market share, double that of the closest competitor, Wys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pro-350
The Professional 325 (PRO-325), Professional 350 (PRO-350), and Professional 380 (PRO-380) are PDP-11 compatible microcomputers. The Pro-325/350 were introduced in 1982 and the Pro-380 in 1985 by Digital Equipment Corporation (DEC) as high-end competitors to the IBM PC. History Like the cosmetically similar Rainbow 100 and DECmate II (also introduced at that time), the PRO series uses the LK201 keyboard and 400KB single-sided quad-density floppy disk drives (known as RX50), and offers a choice of color or monochrome monitors. For DEC, none of the three would be favorably received, and the industry instead standardized on Intel 8088-based IBM PC compatibles which are all binary program compatible with each other. In some ways, the PDP-11 microprocessors are technically superior to the Intel-based chips. While the 8088 is restricted to 1MB of memory because of its 20-bit address bus, DEC microprocessors are capable of accessing 4MB with their 22-bit addressing (although direct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arrow Keys
Arrow keys or cursor movement keys are keys on a computer keyboard that are either programmed or designated to move the cursor (computers), cursor in a specified direction. The term "cursor movement key" is distinct from "arrow key" in that the former term may refer to any of various keys on a computer keyboard designated for cursor movement, whereas "arrow keys" generally refers to one of four specific keys, typically marked with arrows. Arrow keys are typically located at the bottom of the keyboard to the left side of the numeric keypad, usually arranged in an inverted-T layout but also found in diamond shapes and linear shapes. Arrow keys are commonly used for navigating around documents and for playing games. The inverted-T layout was popularized by the Digital Equipment Corporation LK201 keyboard from 1982. Historical development Before the computer mouse was widespread, arrow keys were the primary way of moving a cursor on screen. Mouse keys is a feature that allows c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rainbow-100
The Rainbow 100 is a microcomputer introduced by Digital Equipment Corporation (DEC) in 1982. This desktop unit had a monitor similar to the VT220 and a dual-CPU box with both Zilog Z80 and Intel 8088 CPUs. The Rainbow 100 was a triple-use machine: VT100 mode (industry standard terminal for interacting with DEC's own VAX), 8-bit CP/M mode (using the Z80), and CP/M-86 or MS-DOS mode using the 8088. It ultimately failed to succeed in the marketplace which became dominated by the simpler IBM PC and its clones which established the industry standard as compatibility with CP/M became less important than IBM PC compatibility. Writer David Ahl called it a disastrous foray into the personal computer market. The Rainbow was launched along with the similarly packaged DEC Professional and DECmate II which were also not successful. The failure of DEC to gain a significant foothold in the high-volume PC market would be the beginning of the end of the computer hardware industry in New En ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DECmate
DECmate was the name of a series of PDP-8-compatible computers produced by the Digital Equipment Corporation in the late 1970s and early 1980s. All of the models used an Intersil 6100 (later known as the Harris 6100) or Harris 6120 (an improved Intersil 6100) microprocessor which emulated the 12-bit DEC PDP-8 CPU. They were text-only and used the OS/78 or OS/278 operating systems, which were extensions of OS/8 for the PDP-8. Aimed at the word processing market, they typically ran the WPS-8 word-processing program. Later models optionally had Intel 8080 or Z80 microprocessors which allowed them to run CP/M. The range was a development of the VT78 which was introduced in July 1977. VT78 Introduced in July 1977, this machine was built into a VT52 case and had an Intersil 6100 microprocessor running at 2.2 MHz. The standard configuration included an RX02 dual 8-inch floppy disk unit which was housed in the pedestal that the computer rested on. DECmate Introduced in 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VAXstation
The VAXstation is a discontinued family of workstation computers developed and manufactured by Digital Equipment Corporation using processors implementing the VAX instruction set architecture. VAXstation systems were typically shipped with either the OpenVMS or ULTRIX operating systems. Many members of the VAXstation family had corresponding MicroVAX variants, which primarily differ by the lack of graphics hardware. VAXstation 100 The VAXstation 100 is an intelligent graphics terminal (also described as a ''Display subsystem'') introduced by Digital in May 1983 for the VAX-11 line of computers. The VAXstation 100 was Digital's first workstation hardware for the VAX platform; the graphics terminal approach was selected due to the lack of availability of a VLSI VAX CPU necessary to create a standalone VAX workstation when the project began in 1981. The VAXstation 100's design was based on two internal research projects at Digital - a dedicated VAX workstation named ''SUVAX'' (Si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asynchronous Serial Communication
Asynchronous serial communication is a form of serial communication in which the communicating endpoints' interfaces are not continuously synchronized by a common clock signal. Synchronization ( clock recovery) is done by data-embedded signal: the data stream contains synchronization information in a form of start and stop signals set before and after each payload transmission. The start signal prepares the receiver for arrival of data and the stop signal resets its state to enable triggering of a new sequence. A common kind of start-stop transmission is ASCII over RS-232, for example for use in teletypewriter operation. Origin Mechanical teleprinters using 5-bit codes (see Baudot code) typically used a stop period of 1.5 bit times.Dead link: 2015-Oct-03 Very early electromechanical teletypewriters (pre-1930) could require 2 stop bits to allow mechanical impression without buffering. Hardware which does not support fractional stop bits can communicate with a device that use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ASCII
ASCII ( ), an acronym for American Standard Code for Information Interchange, is a character encoding standard for representing a particular set of 95 (English language focused) printable character, printable and 33 control character, control characters a total of 128 code points. The set of available punctuation had significant impact on the syntax of computer languages and text markup. ASCII hugely influenced the design of character sets used by modern computers; for example, the first 128 code points of Unicode are the same as ASCII. ASCII encodes each code-point as a value from 0 to 127 storable as a seven-bit integer. Ninety-five code-points are printable, including digits ''0'' to ''9'', lowercase letters ''a'' to ''z'', uppercase letters ''A'' to ''Z'', and commonly used punctuation symbols. For example, the letter is represented as 105 (decimal). Also, ASCII specifies 33 non-printing control codes which originated with ; most of which are now obsolete. The control cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LK421
The LK421 was a detachable computer keyboard manufactured by Digital Equipment Corporation of Maynard, Massachusetts and supplied as an option to the standard LK401 keyboard with their DEC 3000 AXP workstations. The keyboard is optimized for use with the Digital Unix line of operating systems, instead of the OpenVMS operating system for which the LK401 was more suitable. The keyboard is notable for the standard position of the Control key for use with Unix operating systems and an Escape key. The keyboard has two compose key A compose key (sometimes called multi key) is a key on a computer keyboard that indicates that the following (usually 2 or more) keystrokes trigger the insertion of an alternate character, typically a precomposed character or a symbol. For insta ...s. There is no separate numeric keypad or edit key group. The functionality of the missing keys is implemented by some standard keys having a dual function. The user holds down the Extend key and presses the k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unix
Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and others. Initially intended for use inside the Bell System, AT&T licensed Unix to outside parties in the late 1970s, leading to a variety of both academic and commercial Unix variants from vendors including University of California, Berkeley ( BSD), Microsoft (Xenix), Sun Microsystems ( SunOS/ Solaris), HP/ HPE ( HP-UX), and IBM ( AIX). The early versions of Unix—which are retrospectively referred to as " Research Unix"—ran on computers such as the PDP-11 and VAX; Unix was commonly used on minicomputers and mainframes from the 1970s onwards. It distinguished itself from its predecessors as the first portable operating system: almost the entire operating system is written in the C programming language (in 1973), which allows U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
